Reproduction and gametogenesis features of Anodonta anatina in Anzali Wetland, Southwest Caspian Sea

Duck Mussel, Anodonta anatina, is the most important native mussel in Anzali Wetland, Southwest Caspian Sea. In the last two decades, its population has been threatened by manipulation and pollution of habitat. Therefore, more studies on biological characteristics are necessary for future conservation. Gametogenesis and temporal changes of the gonads throughout the reproductive cycle were investigated through standard histology. All specimens were gonochoristic with a sex ratio of ۱.۵ F: ۱ M. Gametogenesis has been continuous throughout the year. Three stages, developing (spring and summer), spawning (autumn, September), and post-spawning (winter), were detected in both sexes during a maturation period. Glochidia were present in the gills in January. Five continuous stages were observed in female gonad acini including oogonia; previtellogenic oocytes; pedunculated oocytes; oocytes and mature oocytes. Spermatogonia, spermatocyte, spermatid and spermatozoa were found in male gonad acini. The sexual pattern was asynchronous due to the simultaneous presence of different stages of oogenesis and spermatogenesis in gonadal acini. According to the results, in order to protect the Anodont of Anzali Wetland, especially in the period of September to February of each year, due to the critical time for reproduction of this species, conservation plans should be performed by the Environmental Protection Organization.

کلیدواژه ها:

Swan Mussel ، Anzali Wetland ، Oogenesis ، Sex ratio ، Spermatogenesis